Great writeup on Dynamic Compression

Ivoryk3ys78 said
Hey YR What are the cam specs you are running with the 11:1CR?

My dad's 383 is iron headed with 915 heads. They were heavily shaved and ported. It is all cced out and is a true 11:1. He has an Ultradyne solid roller with 254@050 intake and 110 LSA. Our best octane here is 92. I've never heard his engine ping. I know he runs right at 38. The engine does not run hot.

Wallace racing has a Cranking cylinder pressure calculator. You also get an estimate if you use the dynamic compression calculator there. I don't know how accurate those estimates are.

Cranking Pressure Calculator

The card says 283/283 seat timing, 255/255 at .050 with .620/.620 lift using 1.6 rockers on a 105 LSA installed at 105 (so straight up) and a .014/.016 hot lash.

After talking with Jim at Racer Brown once I had it up and running, he said if I want the seat timing at .020 lift like Comp and some others calculate it, it's actually 280/280 seat to seat.

That's why I say it is 280/280 seat timing because most companies use the .020 lift number and not the lash number.